Researchers at the National Institute of Standards and Technology (NIST) have found a new way to use the built-in compass (magnetometer) in smartphones to measure tiny amounts of important compounds in the body, like glucose and pH levels. This technique uses a special type of material called a hydrogel, which changes shape when it comes into contact with certain substances. Tiny magnetic particles are embedded in the hydrogel, and as the hydrogel expands or contracts, it changes the magnetic field detected by the phone’s compass. This allows the phone to measure the concentration of substances in a liquid sample with high accuracy.
The method is simple, inexpensive, and doesn’t require any special equipment beyond a smartphone. It could be used to detect health markers like glucose in saliva or histamines in urine, which are usually measured in labs. It could also help with environmental testing, like measuring the pH of water. While the technique is still in the research phase, future improvements could make it a practical tool for at-home health monitoring and field testing. The next steps include developing mass-produced hydrogel strips that are stable and react quickly to changes in their environment.
Keywords: Magnetometer, Hydrogel, Glucose Detection
